Experimental investigation on feedback insensitivity in semiconductor ring lasers.

The insensitivity to optical feedback is experimentally measured for a semiconductor ring laser (SRL) and compared to that of a Fabry-Perot laser (FPL) fabricated with the same technology and on the same material. An analysis of the optical spectra reveals that the SRL remains nearly unaffected for values of optical feedback as strong as -23  dB. Furthermore, through both optical linewidth and self-mixing measurements, we show that the tolerance to feedback in SRLs is 25-30 dB stronger than in FPLs.

Polarization-entangled photon pair sources based on spontaneous four wave mixing assisted by polarization mode dispersion.

Photonic-based qubits and integrated photonic circuits have enabled demonstrations of quantum information processing (QIP) that promises to transform the way in which we compute and communicate. To that end, sources of polarization-entangled photon pair states are an important enabling technology. However, such states are difficult to prepare in an integrated photonic circuit.

Correlated photon pair generation in AlGaAs nanowaveguides via spontaneous four-wave mixing.

We demonstrate a source of correlated photon pairs which will have applications in future integrated quantum photonic circuits. The source utilizes spontaneous four-wave mixing (SFWM) in a dispersion-engineered nanowaveguide made of AlGaAs, which has merits of negligible two-photon absorption and low spontaneous Raman scattering (SpRS). We observe a coincidence-to-accidental (CAR) ratio up to 177, mainly limited by propagation losses.

Low-power continuous-wave four-wave mixing wavelength conversion in AlGaAs-nanowaveguide microresonators.

We experimentally demonstrate enhanced wavelength conversion in a Q∼7500 deeply etched AlGaAs-nanowaveguide microresonator via degenerate continuous-wave four-wave mixing with a pump power of 24 mW. The maximum conversion efficiency is -43  dB and accounts for 12 dB enhancement compared to that of a straight nanowaveguide. The experimental results and theoretical predictions agree very well and show optimized conversion efficiency of -15  dB.

Experimental investigation of anti-colliding pulse mode-locked semiconductor lasers.

We experimentally demonstrate anti-colliding pulse mode-locking (ACPML) in an integrated semiconductor laser. The device geometry consists of a gain section and a saturable absorber (SA) section located immediately next to one of the cavity facets. After depositing a low-reflection coating on the SA facet and a high-reflection coating on the gain section facet, the threshold is unchanged, while the modulation of the SA is increased.

Multiwavelength super-structured Bragg grating laser for tunable repetition rate mode-locked operation.

A multiwavelength laser based on a super-structured Bragg grating is designed and fabricated on multiquantum well AlGaInAs-InP. This laser exhibits phase locking via mutual injection of the neighboring cavities assisted by four wave mixing. We present optical and electrical characterization of its emission regimes showing a complex dynamic behavior.

Optical phase conjugation in phase-modulated transmission systems: experimental comparison of different nonlinearity-compensation methods.

We experimentally compare the effectiveness of three different optical-phase-conjugation-based nonlinearity-compensation strategies on a transmission system employing phase-modulated signals, and hence affected by the Gordon-Mollenauer effect. We demonstrate that it is possible to obtain significant nonlinearity compensation, but that no improvement is obtained using configurations specifically aimed at the compensation of the nonlinear phase noise.